Apparatus for refrigeration



Dec. 8, 1925.

B. B. HOLMES APPARATUS FOR REFRIGERATION Filed Feb. 13, 1922 2 Sheets-Sheet l 45 V j 44 5/ A A u flaw 13. m4.

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Dec. 8 1925- 1.564.242 B. B. HOLMES APPARATUS FOR REFRIGERATI ON Filed Feb. 13. 1922 2 Sheets-Sheet 2 gin vent 01,

Patented Dec. 8, 1925.

isnanronh B. normals, on NEW YORK, n. Y.

APPARATUS FOR REFRIGERATION.-

Application filed February 13, 1922. Serial No. 536,170.

T 0 all whom it may concern:

Be it known that I, Bum-one B. HoLMEs, a. citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Apparatus for Refrigeration, of which the following is a specification.

This invention relates to refrigeration, and particularly toa method of operating plantsin which the pumping unit is of the ejector type, and to a refrigerating mechanism of this type particularly adapted to operate according to such method.

The invention probably has its greatest field of utility in domestic refrigeration, where simplicity, compactness, low cost of installation, safety and automatic operation .arethe controlling considerations, but it can be so designed as to give the utmost efiiciency of which the ejector type of refrigerator is capable. To enable the .con-

trolling principles to be fully understood and to avoid any possible implication that the use of special or highly refined types of ejector mechanism is essential, 1 illustrate a simple type of ejector, but I contemplate the adoption, in practise, of the various refinements of ejector design known to those skilled in the art. In other words the design of the device imposes practically no limitation on the design of the. ejector.

In prior refrigerating devices of the ejector type it hasibeen the universal practise to operate continuously, or at any rate the design has been limited to a device capable of continuous operation and in its normal duty operating continuously for long periods. In all such devices the pressure in the boiler and the pressure in the evaporator are respectively higher and lower thanthe pressure in the. condenser, and the condensate must be returned to each if the action is to be maintained. This imposes the necessity of roviding some means of feeding the oondiensate back to the boiler and evaporatorwhile maintaining these d1fler ential pressures. Various arrangements, some depending on the use of pumps and injectors, and others depending on the static head of a column of the liquid condensate have been proposed. Pumps and injectors require too much supervision and the use of the static head exceeds the space limits usu-v ally met in domestic installations.

The present invention ofi'ers a new mode of operation of ejector machines iuwhich the device operates in a succession of thermal cycles, with brief intermissions in which the condensate is fed back from the condenser to the boilerv and eva orator. This action is secured as a result 0 eriodic pressure equalizations between bofler'and condenser which occur as a result of boiling away of the liquid in the boiler.

This back-flow is v caused to take place through large ports, so as to be rapid enough to fill the boiler and replenish the evaporator before rapid vaporization of liquid in the boiler can commence, even though heat is continuously supplied to the boiler. I

i To ensure an adequate duration of backfl o'w the back-flow is initiated by equalization of pressure but can be terminated only by restoration of the maximum liquid level in the boiler, As a further refinement, I

prefer to suliject the termination of back flowpartially to the attainment of a boiling temperature in the boiler, by the use of a valve-controlling float which has increased buoyancy at or near boiling temperature. Such a float is simple to construct and ensuresincreased initial closing force on the back-flow valve, together with slightly retarded closing action.

A preferred embodiment of the invention is illustrated in the'accompanying drawings, in which,

Fig. 1 is a view partly in elevation and partly in section showing the complete device. I

Fig. 2'is a section on line 2-2 of Fig. 1. 3'is a section on the line 3--3 of iig. 4 is a section on the line 4--4 of Fig. 2. Fi the oat valve.

Fig 6 is an enlar ed view of the latch trip mg device whic allows the gas valve to c ose in case the device becomes overheated.

The boiler consists of a. shell 11 and a heat storing'bottom 12 formed with internal fins 13 and external fins 14. These fins serve 5 is a view of the face of the seat'for perature in the condenser.

as means to absorb heat from the heating element in the intervals between the operative thermal cycles, and to impart such heat rapidly to the liquid in'the boiler during the initial portions of the operative thermal cycles, as well as to provide a large heat-absorbing and heat-transmitting surface... The use of fins is not essential.

Surrounding the sides of the boiler is a casing 15 spaced therefrom and having vent ports 16 for the products of combustion. Any suitable offtake for the products of combustion might be substituted and where conveniently possible I contemplate discharge of the products of combustion in such manner as to minimize radiation of heat to the condenser as will readily be understood.

The heating unit may be of any known kind, but should be susceptible of regulation as to its heating effect. In the drawing I show a Bunsen gas burner 17 of which the heating effect may be adjusted by a valve 18.

Under certain abnormal conditions it is desirable to terminate the heating action automatically. As typical of devices for performing this function I show a valve 19 in series with valve 18, but normally held fully open by a latch 20 against the closing effect of a spring 21. tripped by a corrugated metal bellows chaphragm motor 22 when fluid pressure is generated in a chamber 23 connected thereto by pipe 24. The chamber 23 contains a volatile liquid and is subject to the tem- The volatile liquid is chosen with reference to its boiling point, so that it will boil and generate sullicient pressure to operate motor 22 at the desired maximum temperature in the condenser. When ethylchloride is used as the refrigerant, water may be used as the volatile liquid, and still keep the pressure of the ethyl chloride vapor within safe limits, but I prefer liquids having somewhat lower boiling points. 1

The condenser comprises a shell 25 mounted on boiler shell 11 by means of a ported casting 26 and cooled by water circulated in the continuous coils 27. The coils 27 surrounded chamber 23. The terminal connections to the coils 27 are shown at 28 and 29 and circulation of cooling water is produced in any of the ways familiar to those skilled in the art. The amount of cooling water required is small so that in many cases water from the domestic supply may be advanta geously be fed througlrthe coils and discharged to waste. Where water is scarce the familiar expedient of thermo-siphon circulation through coils 27 and a radiator may be adopted.

The casting 26 is formed with a condensate return port 30 and a vent port 31 which communicates throurh a pipe 32 with a T point Within the condenser above the maxias to ensure tight sealing.

The latch 20 is mum condensate level therein. The port 31 is to assure free flow of condensate from the condenser to the boiler through port 30 and has the additional function of connecting port 33 leading to low pressure gauge 34 constantly with the interior of the condenser.

The ports 30 and 31 terminate in the lower face of casting 26, where each is surrounded by a corresponding annular rib or boss 35. The bosses 35 serve as seats for a disc valve 36, which may be of cork or any other suit able material,.and so localize the pressure The valve 36 is actuated by afloat 37 which consists of an inverted cup. The float 37 is fast on a vertical rod 38 which slides in a guideway 39 in casting 26 and which extends downward below the float so as to limit the downward movement of the fioat by the collision of the lower end of the rod with the bottom 12 of the boiler. In order to render the valve 36 self-aligning it fits loosely on a rod 38 and is loosely confined between a spherical boss 54 on float 37 and a stop on rod 38.

Y The casting 26 is provided with a port 40,

shown as a transverse groove which, regardless of the position of valve 36, offers constant communication from the boiler to port 41 leading to high pressure gauge 42 and also constant communication from the boiler to nozzle 43 of. an ejector whose combining tube'is shown at 4-4. Surrounding the combining tube 44 is an annular space 45, which communicates with the entrance end of the combining tube, and to this space 45 is connected the evporator, later to be described.

The combining tube has an upward tubular extension 46 which discharges through the bottom of, and thus into, a cup 47. The cup 47 is supported within the condenser shell, partly by extension 46 and partly by pipe 32 which extends through the bottom of the cup and upward to a'point well above the rim of the cup. Mounted above the cup 47 and below the coils 27 is an inclined bafile or deflector 48 which catches condensate dripping from coils 27, and prevents it from running directly into the cup 47, butdischarges it past the side of cup 47 and causes it to accumulate in the lower part of the condenser shell 25.- The deflector 48 also directs vapor discharging from tubular extension' 46 upward and to one side of shell 25 and thus assists in causing this vapor to circulate in contact with coils 27. The deflector 48 is supported by pipe 32 which extends through and-terminates above it.

The evaporator is simply a closed liquid container with a vapor ofitake leading from a point above the maximum liquid level. In Fig. 1 it is shown as a closed annular evaporator casing 49 connected by a pipe 50 with the space 45 which is the suction intake what more than sufficient of the refrigerant liquid for one operative cycle.

As the action of the evaporator is intermittent and as condensed refrigerant returning to the evaporator conveys some heat .liquid in the boiler will be exhausted and to the evaporator I submerge the casing 49 in a brine bath contained in tank 51. This bath has asteadying effect on the temperature and is used solely for that purpose.

A suitable liquid is introduced intocham-.

her 23 through port 52 which is then closed by its screw plug.

A suitable refrigerant liquid preferably ethyl chloride is poured into the condenser through filling port 53. .The quantity is suflicient to fill the boiler until float 37 seats I valve 36 and to fill the evaporator to the boiled oil through the filling opening and proper level (just below the end of pipe 50). A slight excess is added so that it may be thus sweep the apparatus free of air. When the air is swept out by the vapor, the filling opening 53 is tightly plugged as shown.

Assuming that the apparatus has been properly charged with refrigerant liquidand freed from air, as above described,the flow of cooling water to the coils 27 is started and the burner 17 is lighted and adjusted to maintain the proper boiler pressure..

In charging the device the boiler is filled to a level which would cause the float 37 to close the valve 36 against the seat 35. Assopn as the refrigerant in the boiler reaches its boiling temperature vapor under pressure begins to discharge ,through the nozzle 43 reducing the pressure in the evaporator 49. The vapor from the nozzle 43 together with the vapor drawn from the evaporator 49 is condensed within the condenser shell 25 through the cooling action of the coils 27. The condensate drips from the coils, strikes the deflecting baffle 48 and accumulates in the bottom of the shell 25.

Under ordinary conditions I find it isatisfactory and practicable to maintain apressure of 60 to 80 pounds gauge in the boiler and 8 to 10 pounds in the condenser. With these pressures and using a jet having appro 'mately a inch orifice it is practicable to maintain in the evaporator a vacuum of from to inches of mercury which corresponds to a temperature ranging from to 5 F. approximately. The temperature of the evaporator canthus be regulated by regulating the boiler pressure.

The valve 36 is initially closed by the float 37 and is maintained closed by the differential pressure between the boiler and the condenser regardless of the liquid level so long as that differential pressure continues,

and it will continue until the liquid in the boiler is entirley vaporized and substantially entirely discharged through the noz-' zle 43. This results in the gradual rise of the condensate level in the condenser shell 25 until this level rises above the rim of the or partially fills the cup 47.

At about the time the cup is filled the boiler and condenser pressures will substantially equalize through the ejector nozzle 43. The valve 36 and float 37 then fall of their own weight. The condensate in the bottom of shell 25 rapidly discharges through the port 30, the port 31 servin as a vent to facilitate the flow. Cold con ensate flowing over the Walls of the cup 47, chills this cup and. condenses any vapor within it, thus partially destro ing the pluoyancy of the float 37 during t is back- The liquid level rapidly risesin the boiler tending to lift the float 37 and close the valve 36 against its seat 35,.and at or about liquid frointhe float by vapor bubbles rising i cup 47, whereupon the condensate wholly from the bottom of the boiler, ai1d the resulting increased vapor pressurewithin the in the condenser shell 35 is flowing through port 30 to the boiler the liquid condensate in the cup 47 returns through the tubular extension 46, combining tube 44, space 45 and this resumption occurs shortly after valve- 36 has seated, through theboiling of liquid in the boiler.

lVhile the condensate in the lower portion The effect of the ribs 13 and 14 onthe bottom 12 of the boiler is to absorb heat during the back-flow interval and to impart this heat to the returned condensate so as to shorten the period of inaction after the condensate has flowed back. They also increase the heat-abosrbing and heat-transmitting surface ofthe bottom 12.

In the operation of a device of this character there are only two dangers to be guarded against. The first is the effect of too much heat, and the second is the failure of the cooling water. The first danger is guarded against by so limiting the opening movement of valve 18 that the burner cannot raise the boiler pressure above a desired maximum. Should the supply of cooling water fail, the pressure in the system will rise until the pressure in the condenser reaches a point where the ejector ceases to function and as a result the vapor feeds back to the evaporator which is the coldest part of the system. The refrigerant condenses and accumulates in the evaporator, its level rising above the end of the pipe 50. The volume of the evaporator is made great enough to contain all the liquid in the system. In a short time there will not be liquid enough in the boiler to operate the float and the ports 30 and 31 will remain open so that the condenser and boiler pressures equalize. If the heating action continued the temperature would ultimately reach a point at which the radiation of heat would balance the supply of heat by the gas flame. Before this occurs, however, the liquid in the chamber 23 will boil and by exerting pressure on the diaphragm motor 22 will operate the latch 20 and allow the valve 19 to close under the action of its spring.

To put the apparatus again into action the flow of cooling water is started. This will so reduce the temperature as to induee'a back-flow of refrigerant liquid from the evaporator to the condenser and thence to the boiler. If the burner is then lighted the apparatus will start to perform its normal functions.

From the above description it will 'be apparent that the device is characterized by the absence of any moving parts except the float valve and that this float valve is located at a hot part of the system so that there is no danger of its freezing up.

Various changes in the arrangeu'lent of.

the parts may be made and I wish particularly to mention the fact that the port 2-51 is not absolutely essential but it is useful for the reason that it accelerates the back-flow of liquid to the boiler.

I contemplate the use of any controllable heating element and any suitable automatic means for shutting down the heating element upon abnormal rise of condenser temperature.

- I also crmtemplate the use of various types of ejector mechanism and expect to avail myself of such refinements in ejector design are familiar to'those skilled in the art. Various refrigerant liquids other than ethyl chloride may be used.

It is not absolutely essential that the condensed refrigerant shall return to the evaporator by back-flow through the ejector but I prefer this arrangement because of its simplicity. Obviously also more than one evaporator may be used provided some suit-- able means is used to distribute the returning refrigerant properly to the various evaporators. Details of this sort are not 8.

part of the present invention and are not illustrated for that reason. The possiblity of the use of such details in devices embodying the present invention is specifically recognized.

What I claim is 1. In a refrigerating machine, the combinat-ion of a boiler; a condenser; a volatile liquid in said boiler and condenser; an evaporator also containing such volatile liquid; an ejector interposed between the boiler and condense and connected with said evaporator to draw vapor from the evaporator and discharge it into the condenser; means for periodically stopping the action of the jetof the ejector; and means for supplying condensate to' the discharge end of the ejector during the periods of jet inaction to permit condensate to feed back to the avaporator.

In a refrigerating machine, the combination of a system including a boiler, a condenser, an evaporator, and an ejector, said ejector being connected to discharge into thecondenser, and operable by pres sure vapor from the boiler to draw vapor from the evaporator, a volatile liquid in said system; means for heating the boiler; means for effecting periodic equalization of boiler and condenser pressures, whereby the ejector is periodically rendered inactive; a valve controlling flow of condensate from the condenser to the boiler; and actuating means for said valve operable by such equalization of pressures to open said valve, and by rise of liquid level in the boiler to close the same.

3. In a refrigerating machine, the conr bination of a system including a boiler, a condenser, an evaporator, and an ejector, said ejector being connected to discharge into the condenser, and operable by pres sure vapor from the boiler to draw vapor from the evaporator; a volatile liquid in said system; means for heating the boiler; means for effecting periodic equalization of boiler and condenser pressures, whereby the ejector' is periodically rendered inactive; means for causing condensate to flow from the condenser to the evaporator during such periods of inaction; a valve controlling flow of condensate from the condenser to the boiler; and actuating means for said valve operable by such equalization of pressures to open said valve, and by rise of liquid level in the boiler to close the same.

4. In a refrigerating machine, the combination of a system including a boiler, a. condenser, an evaporator, and anejector, said ejector being connected to discharge into the condenser, and operable by pressure vapor from the boiler to draw vapor from the evaporator; a volatile liquid in said system; means for heating the boiler; means for effecting per1od1c equalization of boiler and condenser pressures, whereby the ejector is perodically rendered inactive; means for establishing a back-flow of condensa-te from the condenser through the ejector to the evaporator during such periods of inaction; a'valve controlling flow of condensate from the condenser to the boiler; and actuating means for said valve operable by such equalization of pressures to open said valve, and by rise of liquid level in the boiler to close the same.

5. In a' refrigerating machine, the combination of a system including a boiler, a condenser, an evaporator, and an ejector,

said ejector being connected to discharge into the condenser, and operable bypressure vapor from the boiler to draw vapor from the evaporator; a volatile liquid in said system; means for heating the boiler; two condensate reservoirs in said condenser, the second of which is fed by over-flow from the first and is in position to feed condensate to the evaporator by back-flow through the ejector when the ejector is inactive; means for effecting periodic equalization of boiler and condenser pressures whereby the ejector is, periodically rendered inactive; a valve controlling flow of con-' densate from the first condensate reservoir to the boiler; and actuating means for said valve operable by such equalization ofpressures to open said valve, and by rise-of liquid level in the boiler to close the same.

- 6. In a refrigerating machine, the com-- bination of a system including a boiler, a condenser, an evaporator, and an e ector,

said ejector being connected to discharge into the condenser, and operable by pressure vapor from the boiler to draw vapor from the evaporator; a volatile liquid in said system; means for heating the boiler; two condensate reservoirs in said condenser, the second of which is fed by over-flow from the first and is in position to feed condensate to the evaporator by back-flow through the ejector when the ejector is inactive; means for effecting periodic equalization of boiler and condenser pressures whereby the ejector is periodically rendered inactive; a valve controlling flow of condensate from the first reservoir to the boiler, and capable of being held closed by preponderance of boiler pressure over condenser pressure; and a float operatively connected with said valve to move the same in a closing direction as the liquid level in the boiler rises.

7. The combination with a boiler anda condenser subject to periodic equalization of pressure, of a valve for controlling the back-flow of condensate from the condenser to the boiler; and an inverted open cuplike float subject to the liquid level in the boiler and connected with said valve to actuate the same, said float being in the path of condensate flowing to the boiler through said valve, whereby the float is cooled and its buoyancy is reduced during said back-flow.

In testimony whereof I have signed my name to this specification.v

BRADFORD B. HOLMES. 

